package com.nowcoder.community.entity;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * @author 花木凋零成兰
 * @date 2024/3/4 22:30
 * 封装分页相关的信息
 */
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class Page {

    // 当前页码
    private int current = 1;

    // 显示上限
    private int limit = 10;

    // 数据总数(用于计算总页数)
    private int rows;

    // 查询路径(用于复用分页链接)
    private String path;

    /**
     * 获取当前页的起始行
     */
    public int getOffset() {
        return (current-1) * limit;
    }

    /**
     * 获取总页数
     */
    public int getTotal() {
        if (rows % limit == 0) {
            return rows / limit;
        } else return rows / limit + 1;
    }

    /**
     * 获取起始页码
     */
    public int getFrom() {
        int form = current-2;
        return Math.max(form, 1);
    }

    /**
     * 获取结束页码
     */
    public int getTo() {
        int to = current+2;
        int total = getTotal();
        return Math.min(total, to);
    }

}
